Yesterday he called ____me ____my office and told me the good news.

A．at, at

B．on, on

C．at, on

D．on ,at

天线增益一般用dBi和dBd表示，请问同一天线的dBi比dBd多多少？（）

A.1.25

B.-1.25

C.2.15

D.-2.15